.banner{
    width: 100%;
    height: 300px;
    background:url(../img/product\ banner.jpg)  no-repeat center;
    background-size: cover;
}
.prcenter{
    padding-top: 50px;
    overflow: hidden;
    width: 1200px;
}
.productsec{
    width: 100%;
    margin: 0 auto;
}
    .productsec .bigitem{
        position: relative;
        width: 33.3%;
        height: 360px;
        float: left;
        position: relative;
    }
    .bigitem img{
        display: block;
        margin: 0 auto;
        width: 360px;
        height: 320px;
    }
    .bigitem p{
        position: absolute;
        left: 30%;
        top:320px;
        font-size: 14px;
        color: #767676;
    }
    .bigitem .mask{
        background-color: rgba(0,0,0,0.3);
        width: 360px;
        height: 320px;
        margin: 0 auto;
        position: absolute;
        top: 0px;
        left: 0px;
        z-index: 2;
        opacity: 0;
    }
    .mask .line{
        width: 80px;
        height: 1px;
        position: absolute;
        top: 154px;
        left: 0px;
        background-color:#ffffff;
        opacity: 1;
    }
    .mask .math{
        position: absolute;
        top: 131px;
        left: 84px;
        font-size: 30px;
        color: #f8f8f8;
    }
    .bigitem:hover .mask{
        opacity: 1;
    }
    .bigitem:hover .desc{
        opacity: 0;
    }
    .bigitem .desc-m{
        position:absolute;
        top: 171px;
        left: 69px;
    }
    .bigitem.active .mask{
        opacity: 1;
    
    }
    .bigitem.active .desc{
        opacity: 0;
    }
    .prcenter.spa{
        padding-bottom: 200px;
    }
    .top-menu{
        margin-top: 150px;
    }
    .top-menu.special{
        margin-top: 20px;
    }